Urease was purified 112-fold to homogeneity from the microaerophilic human gastric
bacterium, Helicobacter pylori. The urease isolation procedure included a water extraction
step, size exclusion chromatography, and anion exchange chromatography. The purified
enzyme exhibited a Km of 0.3+/-0.1 mM and a Vmax of 1,100+/-200 mumols of urea
hydrolyzed/min/mg of protein at 22 degrees C in 31 mM Tris-HCl, pH 8.0. The isoelectric
point was 5.99+/-0.03. Molecular mass estimated for the native enzyme was 380,000+ …